Langue d'oïl refers to a group of Romance dialects spoken in northern France, which evolved from Latin. It is distinct from Langue d'oc, the dialects spoken in the south. The term "oïl" comes from the word for "yes" in these dialects, contrasting with "oc" in the south. Historically, Langue d'oïl was the language of the medieval courts and literature, influencing the development of modern French. It includes various regional dialects, such as Picard and Norman, and played a significant role in shaping the linguistic landscape of France.